Process of making ammonium nitrate.



UNITED STATES WALTER MILLS, OF

Patented March 15, 1904.

PATENT FFICE.

PROCESS OF MAKING AIVIIVIONlUIVl NITRATE.

SPECIFICATION forming part of Letters Patent No. 754,668, dated March15, 1904.

Application filel May 25, 1903. Serial No. 158,625. (No specimens.)

\ T at whom, it Wmy concern.-

Be it known that I, WALTER MILLs, a subject of theKing of Great Britain,residing in London, England, have invented certain new and usefulImprovements in Processes of Making Ammonium Nitrate, of which thefollowing is a specification.

This invention has for its object the preparation on a commercial scaleof pure nitrate of ammonia through the intermediary of nitrate of lead.The preparation of nitrate of lead is economically effected by theaction of the nitrates-such as nitrate of calcium, potassium, orsodiumon silicofluorid of lead, which latter is readily made by theaction of hydro is assisted by the aid of heat, which is usuallycontinued until the mass has reached a substantially dry condition. Ifgalena or scraplead is used, it is immaterial whether the same be addedto the acid or the acid be added to it. carrying compounds be. used, itis necessary to add the same to the acidthat is, to have the acid ineXcessas otherwise silicates are formed, The acid begins to attack thematerial when of a specific gravity of about 1.80. When scrap-lead isused, the action of the acid is accelerated somewhat by blowing airthrough the mass. Warm water is then added If ores such as cerusite orother oxygen-- to form an aqueous solution of lead silicofluorid. Afterbeingfiltered the solution is ready for the addition of a nitrate, suchas nitrate of calcium, potassium, or sodium, either in aqueous solutionor in fine powder. The silicofluorids of the respective metal areprecipitated, while nitrate of lead remains in solution. For thepreparation of ammonium nitrate from this solution of nitrate of lead Igenerally employ a solution of ammonia or one of its salts, such asfiuor'id of ammonium. It is best to heat the two solutions to atemperature of about 8O Centigrade before mixing; otherwise double saltsin a more or less hydrated condition are frequently formed andprecipitated. Such double salts may, however, be resolved by washingthem with water at about 100 centigrade.

Having described my invention, I claim 1. The process of making ammoniumnitrate which consists in first forming silicofluorid of lead; thenconverting the same into the nitrate; and finally reacting upon thenitrate of lead with fluorid of ammonium.

2. Theprocess of making ammonium nitrate which consists in heating amixture of lead or lead-carrying compound and hydrofiuosilicic acid ofabout 1.80 specific gravity; in addinganitrate to asolution of the leadsilicofluorid so formed; and in finally decomposing the lead nitratewith ammonium fluorid.

Signed at Nos. 9 to 15 Murray street, New York, N. Y., this 23d day ofMay, 1903.

WALTER MILLS.

Witnesses:

FRED. J DOLE, JOHN O. SEIFERT.

